I really hope someone can help me as I've searched the web without success
for UMS firmware/boot loader files for my iRiver H10 20Gb.

Any link I've ever found is either dead or leads me to a page in Korean that
doesn't appear to have anything you can click on that begins a download.

There MUST be someone somewhere that can get these files and I'm hoping that
someone here can help.

I bought my H10 last week and after much hair-pulling have found out that
it's an MTP version which cannot be accessed via my Windows XP machines. I
have since learned that there's a UMS version of the firmware that will
allow me to just plug the player via USB to my PC (as with my iHP-120
player) and I'd dearly love to just be able to get hold of the firmware and
boot loader files to allow me to convert my MTP version to the UMS variety.

Also, if someone can direct me to a link to get these files, I'd also
appreciate a simple guide to upgrading the firmware on my H10. I have no
music on the player at the moment, so am not worried about losing anything.